V2X technology relies on a host vehicle (HV) receiving messages over a dedicated short range communications (DSRC) radio from one or more surrounding vehicles. The primary message used for vehicle-to-vehicle (V2V) communication is the Basic Safety Message (BSM), with the definition of the message defined in SAE J2735 and the rules for its usage defined in SAE J2945/1. The BSM contains a field named the DE_TemporaryID which must be initialized to a random value by each DSRC system transmitting a BSM. The value of the DE_TemporaryID is changed occasionally when the system changes its security certificates, but is not allowed to be changed at any time.
When a host vehicle receives a BSM, the DSRC system uses the DE_TemporaryID to differentiate the surrounding vehicle transmitting the BSM from other surrounding vehicles transmitting BSMs having the different DE_TemporaryID. It is important to maintain previous state information on each surrounding vehicle for various reasons, including:
maintaining accurate Packet Error Rate (PER) calculations on a per vehicle basis, as defined and required in J2945/1;
tracking individual surrounding vehicles in the vicinity of the host vehicle and identifying which vehicles may pose a potential threat to the host vehicle; and
maintaining previous surrounding vehicle information for specific safety application algorithm usage.
The length of DE_TemporaryID is defined as 4 octets (or 32 bits), so there is a ½32 probability where any two DSRC systems will select the identical DE_TemporaryID value when randomly setting an ID number. If one or more surrounding vehicles coincidently set the identical DE_TemporaryID value, the DSRC system may inadvertently over-write each other within the internal data structures. As a result, the vehicle tracking algorithms and safety applications may not recognize the existence of all the nearby surrounding vehicles, and therefore may not detect important V2V safety threats.
In view of the above, it is an object of the present disclosure to provide an apparatus that accurately detects a duplicate temporary ID situation between surrounding vehicles. It is another object of the present disclosure to provide a method for accurately detecting a duplicate temporary ID situation between surrounding vehicles.